When using a measuring cylinder one precaution to be taken is to
A.check for zero error
B.look at the meniscus from below the level of the water
C.obtain more readings by looking from more than one direction
D.position the eye in line with the base of the meniscus
E.make sure that the measuring cylinder is clean
2.10 alamas
Match items in List A with responses in List B by writing the letter of the correct response beside the item number.
(i)
γ-rays
1 alama
(ii)
α-particle
1 alama
(iii)
Cathode ray tube
1 alama
(iv)
Infra-red radiation
1 alama
(v)
Hard x-ray
1 alama
(vi)
Capacitor
1 alama
(vii)
Transistor
1 alama
((viii)
P-type semi-conductor
1 alama
(ix)
Extrinsic semi-conductor
1 alama
(x)
Cathode ray
1 alama
Boresha ili kuona majibu ya mfano.
Sehemu B
3.10 alamas
SECTION B (60 marks)
Answer all questions in this section
((a)(i)
Find the mass of 500 cm3 of brass if the density of water is 1 g/cm3
3 alama
(b)
A cup made of an alloy of gold and silver has a volume of 60 cm3 and a mass of 1050 g. Find the mass of gold contained in the cup.
6 alama
Boresha ili kuona majibu ya mfano.
4.10 alamas
SECTION B (60 marks)
Answer all questions in this section
((a)(i)
Give two examples of couples.
2 alama
(b)
A force of 60 N is acting at an angle of 30° to the horizontal. Find its horizontal and vertical components. Draw a vector diagram of the force and its components.
7 alama
Boresha ili kuona majibu ya mfano.
5.10 alamas
SECTION B (60 marks)
Answer all questions in this section
((a)(i)
Clinical thermometers should not be sterilized in boiling water. Give reasons.
3 alama
(b)
A piece of lead of mass 500 g falls from a height of 25 m. Assuming that all the energy changes into internal energy in the lead when it strikes the ground, calculate the rise in temperature of the lead if its specific heat capacity is 130 J/kgK. (g = 10 N/kg).
4 alama
Boresha ili kuona majibu ya mfano.
6.10 alamas
SECTION B (60 marks)
Answer all questions in this section
((a)(i)
Why does the lightning conductor have a sharp pointed top?
1 alama
((b)(i)
The resistance of a wire of length l is 4 ohms. Calculate the new resistance of the wire when its length is doubled and its volume unaltered.
4 alama
Boresha ili kuona majibu ya mfano.
10.7 alamas
(b)
(i) Mention the main feature which differentiates x-ray tube from the cathode ray tube.
(ii) State the main similarities existing between the features of an x-ray tube and the cathode ray tube.
3 alama
(c)
(i) Except for the “window”, there is a lead shield around the x-ray tube. Explain giving a reason.
(ii) State three (3) uses of cathode ray tube.
4 alama
((a)(i)
In a cathode ray tube, explain how Electrons make the fluorescent screen to glow.
3 alama
Boresha ili kuona majibu ya mfano.
11.10 alamas
(a)
(i) Define transistor.
(ii) Give reasons to explain why npn transistors are used in high frequency circuits and pnp transistors are used in low frequency circuits.
3 alama
(b)
(i) A certain transistor has a current gain of 50. Explain the meaning of this statement in terms of the magnitude of input and output current.
(ii) In a common emitter mode, the base emitter junction is a low resistance junction while the base-collector junction is high resistance junction. Explain.
3 alama
(none)
Figure 2 above shows a pnp transistor fully stabilized. Describe the functions of
(i) capacitors $C_2$ and $C_3$
(ii) resistor $R_4$
4 alama
Boresha ili kuona majibu ya mfano.
Sehemu C
7.5 alamas
7. (a) (i) Define atomic number.
(ii) Explain the effect of emission of β-particle from an atom of radioactive
phosphorus of atomic number 15 and mass number 32.
(b) A radioactive element has a half life of 3 minutes. If the initial count rate is 512
per minute, find the time needed to reach a count rate of 8 per minute.
((a)(i)
Explain the effect of emission of β-particle from an atom of radioactive phosphorus of atomic number 15 and mass number 32.
3 alama
(b)
A radioactive element has a half life of 3 minutes. If the initial count rate is 512 per minute, find the time needed to reach a count rate of 8 per minute.
5 alama
Boresha ili kuona majibu ya mfano.
8.8 alamas
8. (a) (i) Define solar system.
(ii) Describe the force(s) which keep the solar system from breaking apart
(intact).
(b) Distinguish between
(i) a planet and a star
(ii) a comet and a meteor.
(c) The Earth takes one year to orbit the Sun. The distance between the Earth and
the Sun is 150 x 10^6 km. Calculate the speed of the Earth in the orbit.
((a)(i)
Describe the force(s) which keep the solar system from breaking apart (intact).
1 alama
((b)(i)
Distinguish between a comet and a meteor.
2 alama
(c)
The Earth takes one year to orbit the Sun. The distance between the Earth and the Sun is 150 x 10^6 km. Calculate the speed of the Earth in the orbit.
4 alama
Boresha ili kuona majibu ya mfano.
9.10 alamas
9. (a) (i) Differentiate work from energy.
(ii) Explain, giving reasons, why a freely swinging pendulum bob eventually
comes to rest. (3 marks)
(b) (i) State the law of conservation of energy.
(ii) A crate of soda of mass 10 kg was accelerated from a velocity of 10 m/s
to 20 m/s when a force of 50 N was applied on it. Find the displacement
of the crate. (3 marks)
(c) A man wearing a bullet-proof vest stands still on a smooth slippery surface. His
total mass is 80 kg. A bullet of mass 20 grams is fired at a velocity of 400 m/s.
It is stopped by the vest and falls to the ground. Find the velocity of the man
after impact with the bullet. (4 marks)
((a)(i)
Explain, giving reasons, why a freely swinging pendulum bob eventually comes to rest.
3 alama
((b)(i)
A crate of soda of mass 10 kg was accelerated from a velocity of 10 m/s to 20 m/s when a force of 50 N was applied on it. Find the displacement of the crate.
3 alama
(c)
A man wearing a bullet-proof vest stands still on a smooth slippery surface. His total mass is 80 kg. A bullet of mass 20 grams is fired at a velocity of 400 m/s. It is stopped by the vest and falls to the ground. Find the velocity of the man after impact with the bullet.
4 alama
